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In this paper, a novel double-disc straight groove lapping (DDSGL) method is proposed to reduce roundness error and improve surface roughness of tapered rollers. According to the conjugate surface principle and the kinematic characteristics of the tapered roller, the theoretical contour of the grinding tool working surface was designed. The contact relationship between the rollers and the working surface of the grinding tool is established. The relative motion between the tapered rollers and the grinding tool is discussed in detail, and the lapping trajectory on the rolling surface of tapered rollers is calculated and analyzed. The impact of the system's structural parameters (i.e., eccentric circular groove radius, eccentricity, and upper disc circular groove radius) as well as the kinematic parameters (lower disc rotational speed) on the uniformity of the lapping trajectory in the lapping process was explored. The structural parameters of the DDSGL equipment were determined using the standard deviation of the lapping trajectory distributed on the tapered roller rolling surface. Finally, the lapping experiments of tapered rollers were carried out in a homemade equipment, and the results show that the newly proposed method can effectively improve the roundness and reduce the surface roughness of the tapered rollers. [ABSTRACT FROM AUTHOR]

Rolling bearings are extensively employed in the modern machinery industry and are critical industrial base elements. The machining accuracy of bearing rolling elements has a great impact on the service performance of rolling bearings. In this work, advances in the ultra-precision machining of bearing rolling elements are summarized, and corresponding outlooks are presented. An introduction to the accuracy requirement of the rolling element and the corresponding basic principles are first discussed. Subsequently, advancements in the ultra-precision machining of bearing balls are reviewed and analysed. Meanwhile, research progress on the ultra-precision machining of bearing rollers is also summarized and compared with the investigations on bearing balls. It is demonstrated that due to the absence of an intercomparison effect in the machining process, the batch accuracy of the bearing roller is lower than that of the bearing ball. Furthermore, more attention should be given to the machining accuracy of the crown profile and spherical datum surface of the bearing roller. Finally, in regard to the above academic achievements, conclusions and outlooks on the ultra-precision machining of bearing rolling elements are given. The advances and outlooks summarized in this work are beneficial to both academic scientists and industrial researchers. [ABSTRACT FROM AUTHOR]